| Blackened jujube is a new product processed by red jujube,which is formed under specific temperature and humidity conditions.It is black brown,fragrant,soft and waxy,with sweet and sour taste.The appearance,taste and active ingredients of red jujube changed significantly after processing.Polysaccharide is one of the most active components in jujube,which has antioxidant and antitumor functions.At present,malignant tumor is one of the most serious diseases threatening human health and life.It is of great significance to study and discover new anti-tumor drugs with low cost,low toxicity and high efficiency.Compared with red jujube,blackened jujube significantly increased its polysaccharide content and antioxidant activity.At present,the antitumor activity of blackened jujube polysaccharide has not been reported,which greatly limits its application in medicine and functional food fields.Therefore,It is of great significance to study the structural characteristics and antitumor activity of polysaccharides of blackened jujube.In this study,the crude polysaccharides of blackened jujube were extracted and purified by hot water extraction.The physicochemical properties,functional properties and antitumor activity of BJP-2 were studied.The main research contents are as follows:(1)Extraction,separation and purification of crude polysaccharides from blackened jujubeThe crude polysaccharide was extracted by water extraction and alcohol precipitation method.After the lipid soluble substance was removed by petroleum ether and the protein was removed by Sevage method,it was separated and purified again by DEAE-52 cellulose column and Sephadex G-100 chromatography column.BJP-2,one of the main components after purification,was selected for follow-up study.(2)Structural characteristics of polysaccharide BJP-2 from blackened jujubeThe total sugar content of BJP-2 was 92±0.05%and the flavonoid content was 0.81±0.01%.Polyphenol content was 1.68±0.01%,protein content was 0.52±0.01%.The average weight molecular weight was 6.42×10~4 Da and the polydispersity index was 3.797.BJP-2 was composed of Gal A(39.78%),Ara(31.93%),Gal(16.86%),Rha(6.43),Xyl(1.86%),Glc A(1.28%),Glc(1.02%),Fuc(0.61%)and Man(0.23%).The BJP-2 main chain by→5)-α-L-Araf(1→4)-β-D-Gal(1→、T-α-L-Araf(1→4)-β-D-Gal(1→、→4)-α-L-6Me Gal Ap(1→.The results of fourier infrared spectroscopy show that BJP-2 has the characteristic groups of polysaccharide.(3)Physicochemical properties of polysaccharide BJP-2 in blackened jujubeThe physicochemical properties of BJP-2 showed that BJP-2 had good solubility and oil holding power,poor foaming ability and foam stability,and high emulsifying ability and emulsifying stability.This may be related to its larger molecular weight and other structures.(4)The antitumor activity of polysaccharide BJP-2 in blackened jujubeIn vitro anti-tumor experiments showed that BJP-2 had a significant inhibitory effect on Hep-G2 cell viability,which decreased to 55.0±4.00%after incubation at the highest concentration(800μg/m L)for 48 h.Flow cytometry showed that BJP-2 could promote apoptosis of Hep-G2 cells,and the effect was dependent on the concentration of BJP-2.Scratch test showed that the mobility of Hep-G2 cells decreased to 38.45±5.70%and 17.86±2.10%under the treatment of high doses of BJP-2(400μg/m L and 800μg/m L).Transwell assay results showed that BJP-2 inhibited the invasion ability of Hep-G2 cells in a concentration-dependent manner.Westen blot results showed that,compared with the control group,the expressions of Bax,Claved Caspase-3/Caspase-3 and Claved Caspase-9/Caspase-9in Hep G2 cells were significantly increased after BJP-2 treatment(P<0.01).In particular,they increased by 2.54 times,7.6 times and 33.52 times at 800μg/m L(P<0.01). |
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